when the box was closed and the straps drawn tight
around it, a knifelike strip around the edge of the
lid bit deeply into the indium, thus helping to seal
the samples in a vacuum and to protect them
against contamination.
All told, the astronauts brought back about 48
pounds of lunar material. In addition, they under
took to gather a bit of the sun. To be sure, it was a
very small sample, less than a billionth of an ounce
at best, but presumably it was enough to tell a great
deal about the solar furnace. The sample was gath
ered by trapping particles of the solar wind.
Swiss Scientists Count Sun Particles
The solar wind is an ionized, or electrified, gas
constantly streaming away from the sun at speeds
of 200 to 400 miles a second. Ordinarily we do not
detect the wind on earth, because the magnetosphere
-the magnetic field around our planet-deflects
the electrified gas. We see its effects only when a
little of the solar wind occasionally leaks into the
magnetosphere in the polar regions, becomes accel
erated by some process that scientists do not yet
understand, and causes the brilliant aurora high in
the atmosphere.
The moon lacks a strong magnetic field, so the
solar wind flings against it a steady barrage of
atomic particles that, scientists believe, may slowly
erode the lunar rocks. The device to trap these in
finitesimal particles is ingeniously simple, compared
to other more sophisticated instruments designed
for lunar research. It amounts to little more than a
strip of aluminum foil about a foot wide and four
and a half feet long that Aldrin unfurled and hung
on a slender mast stuck into the moon near the
lunar module (left).
This sheet was left exposed to direct sunlight for
an hour and 17 minutes, then rolled up like a win
dow shade and stored inside one of the lunar sam
ple boxes. Scientists hope that during exposure the
sheet received the full force of the solar particles.
Many of them-perhaps as many as 100 trillion
may have embedded themselves in the foil, pene
trating several times their own diameter-as much
as a millionth of an inch.
As this is written, Swiss researchers led by Dr.
Johannes Geiss are attempting to extract the solar
particles at the University of Bern and the Federal
Institute of Technology in Switzerland.
Their technique is to melt and vaporize the foil in
an ultrahigh vacuum. Then, in a device known as a
To catch the solar wind-atomic particles
from the sun that constantly bombard the moon
- Aldrin unfurls a 12-inch-wide, 4
1
/2-foot-long
strip of aluminum foil. Left exposed for 77 min
utes, the sheet was designed to trap particles
for scientists to study back on earth.
EKTACHROME
BY NEILA. ARMSTRONG.NASA